This invention relates to an hydraulically-actuated operating system for operating an electric circuit breaker and, more particularly, relates to a system for reducing flow restriction impedance to high speed opening and closing of the circuit breaker.
The usual hydraulic operating system for producing high-speed operation and control of a circuit breaker typically comprises a main valve and a pilot valve for controlling the main valve. Typically, the pilot valve must be operated from a normal to an operated position to initiate operation of the main valve, which, in turn, initiates operation of the circuit breaker, and must then return to its normal position at the end of the circuit-breaker operation to restore the main valve to its initial position so as to prepare the system for operation of the circuit breaker in a reverse direction. This type of pilot valve operation requires rather involved controls, either electrical or hydraulic. Moreover, the need to first operate the pilot valve tends to increase the time required from the initial starting signal to operation of the main valve.
An approach to overcoming these limitations to actuator operation is disclosed in U.S. Pat. No. 4,118,613 issued Oct. 3, 1978 to Barkan et al. assigned to the instant assignee and incorporated herein by reference thereto. The above-cited patent discloses an hydraulically-actuated operating system for a circuit breaker which employs a fluid motor driven in the breaker opening direction by pressurized liquid and dashpotted by a plug restricting fluid flow through an opening surrounding the operating rod of the fluid motor.